Investigating Augmented Reality Visio-Haptic Techniques for Medical Training

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Timothy R Coles
<p>It is widely accepted that a reform in medical teaching must be made to meet today s high volume training requirements. Receiving pre-training in a core set of surgical skills and procedures before novice practitioners are exposed to the traditional apprenticeship training model where an experienced practitioner must always be present, can reduce both skill acquisition time and the risks patients are exposed to due to surgeon inexperience. Virtual simulation offers a potential method of providing this training and a subset of current medical training simulations integrate haptics and visual feedback to enhance procedural learning.</p><p>The role of virtual medical training applications, in particular where haptics (force and tactile feedback) can be used to assist a trainee to learn and practice a task, is investigated in this thesis. A review of the current state-of-the-art summarises considerations that must be made during the deployment of haptics and visual technologies in medical training, including an assessment of the available force/torque, tactile and visual hardware solutions in addition to the haptics related software. An in-depth analysis of medical training simulations that include haptic feedback is then provided after which the future directions and current technological limitations in the field are discussed.</p><p>The potential benefits of developing and using a new Augmented Reality (AR) visio-haptic medical training environment is subsequently explored, and an exemplar application called PalpSim has been produced to train femoral palpation and needle insertion, the opening steps of many Interventional Radiology (IR) procedures. This has been performed in collaboration with IR experts. PalpSim s AR environment permits a trainee to realistically interact with a computer generated patient using their own hands as if the patient existed in the real world. During a simulation, the trainee can feel haptic feedback developed from in vivo measured force data whilst palpating deformable tissue and inserting a virtual needle shaft into a simulated femoral artery, at which point virtual blood flow from the real needle hub will be seen. The PalpSim environment has undergone face and content validation at the Royal Liverpool University Hospital and received positive feedback.</p><p>An important requirement identified was for a haptics device combining force and tactile feedback to closely simulate the haptic cues felt during femoral palpation. Two cost effective force feedback devices have therefore been modified to provide the degrees of force feedback needed to closely recreate the forces of a palpation procedure and are combined with a custom built hydraulic tactile interface to provide pulse-like tactile cues. A needle interface based on a modified PHANTOM Omni also allows the user to grasp and see a real interventional radiology needle hub whilst feeling simulated insertion forces.</p><p>PalpSim is the first example of a visio-haptic medical training environment based on chroma-key augmented reality technology. It is expected that many other medical training solutions will adopt this approach in the future.</p>